Internal-combustion engine.



P. A. LAWRENCE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED AUG.I m4.

Pat ented July 31, 1917.

Fig. 3

lnvenforpiston is passing sition to admit air into the cylinder, be drawn in as the piston advances,

I PAUL A. LAWRENCE, OF BENSON, NEBRASKA.

'm'rEaNAL-coMBus'rIon ENGINE.

Specification of Letters Patent.

Patented July 31, 1917.

Application filed August 1, 1914. Serial Nd. 354,534.

7 '0 all whom it may concern:

Be it known that I, PAUL A. LAWRENCE, 'a citizen of the United States, residing at Benson, in thefcounty of Douglas and State of Nebraska, have invented a new and useful Improvement in Internal-Combustion Engines, of which the following is a specification.

My invention relates to that class of engines known as the constant pressure type and is applicable to either two cycle or four cycle operation. A four cycle engine is described, having the characteristics of the hypothetical indicator diagram shown in Figure 4:, but this cycle may be modified to secure the characteristic of the diagram Fig. 5, or the mechanism may be so changed after any suitable well known two cycle principle to adapt the engine to two cycle operation.

As the mechanism employed and the mechanical cycle of operation are not essen tial to the basis of this invention,.only one type of mechanism will bedescribed and this has been simplified in order to facilitate understandin and clearness.

The genera. principles of operation'are as follows: a

Starting with the piston at the head end of the stroke and with the valve gear in p0 air will and at the return stroke this air will be compressed until :it reaches a certain presure when a valve opens communicating withv an air receiver containing air of the same pressure, further advance ofthe piston forces the air from the cylinder into the receiver with consequent slight rise in pressure. The cylinder clearance is made as small as possible so that-nearly all the air is forced intothe receiver.

The receiver valve is held open while the the dead center and for of the power stroke depending a portion load, and the air which has been upon the tor-cad into the receiver is allowed to return to the cylinder. The instant the piston begins its oweit stroke, oil sprayed into the returning air by the 011 pump at an accelerating rate- (proportional to the rate of piston travel) andburns as fast'as it meets the air.

- trated by the The governor controls the length of time the oil is injected and a pressure regulator on the receiver, the length of time the receiver valve is open. The oil injection always ceases at or before the time the receiver valve is closed and the receiver valve always closes when the receiver pressure has dropped to the value it had when the receiver valve opened, in other words, when all the air which had been forced into the receiver has returned to the cylinder. The receiver is of such a size that the range of pressure is suflicient to properly work the pressure regulator of the receiver, something like 20 or 40 pounds. The above gives rise to an engine having'a constant compression under all loads, and a nearly constant pressure of combustion, as shown b the hypothetical diagram Figure 4. The otted and solid lines show how the load afi'ects the combustion and expansion lines with a change in load.

The nature of my invention is fully illusaccompanying drawing, though the details of mechanism employed are not essential, but may be of any suitable form to carry out the operation herein laid down. v

Referring to the drawing Fig. 1 is a side view of the rear part of the engine showing the features of my invention, the front part being not unlike that of an ordinary gasolene engine. Fig. 2 is a rear elevation of Fig. 1.

Fig. 3 is a sectional view through the middle of the cylinder, air receiver and oil pump, and has the exhaust valve mechanism and the oil and air mechanism cut away, leaving only ing rod "and rocker arm, intake valve.

Fig. represents which actuates the v a diagram or indicator card drawn to show the action of the gases in the cylinder of the engine described' Fig. 5 is also a drawn indicator card of a modification of the method of controlling the air supply and combustion in the cylinder and is given to illustrate how the valve the intake cam, cam arm, connectgear and 'overnor control may be modified without c anging the essential features of the invention.

Similar letters and the same parts in the different views.

figures correspond to The method of designating'parts is in groups of letters combined with numbers; thus the a g l 7 77, @1577 2, 8, 4, t to the 011 pump and its connections; the-b group to the air receiver valve and its connectlons; the 0 grou to where the aZ roup and 12 group join and are both actuated .by the mechanism common to both, the d group the exhaust valve and its connections; the e group to the air intake valve and its connections; the f group to the spark plug and connections; the g group to-the oil supply pump to draw the oil from a distant source and supply the small tank D'with oil; the h group refers to the cam shaft andconnections.

The rear part of the engine only is shown, the forward-part, consisting of any suitable crank shaft, supported on proper bearings and carrying a. bevel gear, keyed to the crank shaft and meshing into a bevel gear keyed on the forward end' of the diagonal shaft h which is also supported by a proper hearing at each end. A centr fugal governor driven from the crank shaft by belt or gearin is so connected to the rod a that it W111 move it forward with an increase of speed-and backward with a reduction in speed. A connecting rod connects the crank shaft and piston Efwhich,

works in the cylinder, B. The length of the rod is such that the piston comes quite close to the cylinder head D when at the inner dead center or, in other words, the

clearance is made as small as is practically possible. I

An air chamber A is mounted near the cylinder head and communicates with the cylinder is an opening, for'the in'jection of oil. This opening is closed by a valve a held to its seat by a spring. The oil pump plunger 0, on descending, forces the valve w' to open both against the tension of the spring and the pressure of the air in the air passage and drives a thin circular sheet or spray .of oil into the said passage. When the oil pump plunger, a,

ascends it draws ina fresh supplyof oil from the oil tank, D, through the small ball check valve and passage. The top of the air chamber, A, has an opening closed by the-thin metal plate, F held in place by the gland nut F packingbeing 'inagainst the. stop a stufiin box sertedto make the same tight. This combination is intended as a relief by breaking by the coil spring mounted on its stem. d

is the exhaust valve held to its seat by the h is the cam shaft driven from the shaft Ik by means ofthe bevel gears, h and h and rotates. atv one-half the speed of the crank shaft. The cam shaft carries three cams s m and 5 Cam 6 through the mechanism a, e', e, and e" actuates the air intake valve e. Cam cl,through the mechanism d4, en dz, andludi a actuates the exhaust valve d. Cam 0'? through the '87, 05 "(047,, soured by the rod d is not shown in the drawings), 0, c and 0 actuates the lever 0 through'thef'armT-afii, v

' The rod dfliisfl disengaged from the pin a? by comingiinwcoptact with the curved arm a? controlledbfijthejgovern r through therod 0; theuiositibn 0f a? etermines the point at'which athegin'ection of fuel is cut oif. The toggle (f -is drawn, back as th l an and fb";ij' "fa engages the pin th toggle J9 g (1 which in uates l the Soil; injection pump a? as soon as the pawl rod-,faf is unhooked from the pin a by the am -gar.

ted by th .The pawl rod 12* also 0 d operates level: ,c engages the pi nfb' if; thg air receiver valve b-'thro11gh 5 b and the connecting 6" is a small'cylinder connected-to the air chamber .A by means of an .open port 'near the bottom of 'thecylinder. Infthis cylinder is fitted a piston with a coil spring placed on top of it,and held down by the cap" hrough which thei'od passes." The rod connects to the rocker. arm, 129

- Air fromthe chamber, is free topass through the port to'the-undei'side-of the small piston in the-cylinder f,b.'" and forces the piston to rise against theitension of'the s rin with every increase'an pressure in t e chamber, A, and to desccndib'yreason of the opposing force of the spring with the. arm

which has attached to it two pawl every reduction of pressure' i'nythe chamber,

A-. The is'ton .in the? cylinder, 12', in

moving up and down in response to vanations of pressure in the receiver Ai, oscil- 'lates the lever b and raises and lowers the rod 6'. The pin -bi projects from and is secured in the pawl rod 5* and works in' the slot at theend oifb. ith a reduction in pressure in the air receiver A? the rod b ascends until the lower end of the slot comesin contact with the pin .b and carries the pawl rod 6" with it, thus disen-' gaging a from the pin Mama allowing the spring 6" to close the air I'GCGIVGI valve 6, thereby preventing further reductionlofpressure in the air receiver At. a The ignition apparatus f, f and f only in starting while the engine cylinder is cold. These ig iition par ts are connected to an ordinary ump spark coil and f is connected to the coil circuit and f in the battery circuit. When f comes in contact with the battery circuit is completed and a series of arks issue between the points of the spark gin -f. f is formed of a s ringv and is orced out of contactwith fi by the to le a3.

" I y e spring a is for the purpose of re turningthe arm and keeping the roller a and b from engaging the pins 09 incontact with the cam 0.

- The pump 9 is operated through the connectin rod 9"? by an extension of the pin 09, ig. 1, and'keeps the tank D full of oil, the surplus oil being returned to the supply tank through the over-flow he "pipe 1) leads to a small air tank into which air has been compressed by the engine while runningon inertia in. the act ofshutting down. a a

The lever 8 is the starting and stopping lever andoperates by engaging the arm 0 and ,holdingit down against the tension of the ring 0*. This keeps the arm c in a orward position and prevents the 3 and,b', and stops the functioning of the oil. ump a and receiver valve 6 aving described the essential working parts of the engine the operation will be understood by describing a'complete working cycle, starting with the engine at rest. The oil chamber D is drained of 011 and to e the pins ;A l ftv o rkir? I in'position r beginning filled with gasolene.

The crank bait is now turned until it is on the-inner dead center and thecyclepf operation is in the position where 'bothintake and exhaust valves are closed and the valve"b about to open. The" air cock k is for the purpose of relieving the compression while putting the engine in this position.

Admit air into the air receiver A by 0 nin the valve in the pipe p, then close iii: va ve. This fills the receiver A with airof thenormal working pressure. p p

The air cock is is nowv closed and the starting lever a is pushed forward thus" releasing the arm c th spring 8 promptly! arms into the position shown 13 Fig. carrying back the 233181352173, and

parts of the engine are now its first power stroke. By a slight additional movement -sio'n oft egases during the wor iston so that further motion of the 11" thereby lowering t to issue at the spark plug f igniting the mixture as it enters'the cylinder. This action continues until the piston has arrived at approximately i or 1],. of its outward stroke, at which point the pressure in the chamber A has'been' lowered to such an extent that the y ressure regulator b has raised the 'rod to a height that the pin 5 strikes thebottoin of slot in the rod b thus raising the rod 12* out of contact with the pin 'b,allowing the valve b to close. At the same instant a comes in contact with a, releasing it from the pin fa allowing the toggle a? to fly back, stoppin the injection of oil or gasolene and brea ing the battery circuit. a The piston now continues under the expansion force of thegases, the pressurefalling corre'spondingly. At the point d Fig. 4 the exhaust valve 0 ns and u n the inward stroke of the piston the ex aust; gases are forced out. As; the clearance between the cylinder head and piston is reducedto the smallest practical value the cylinder is completely emptied of the exhaust gases.

Upon the second outward stroke of the piston, air is drawn into the cylinder At the same instant by the r through the valve e.- The dam e is; so

formed that the :valve e is held open for a part ofthe following inward stroke therer by allowing fisome' of the air which was drawn nto the cylinder. to passout again IQIS through "the open valve a, the object of" this bein to securea more complfieexpangst'ro'ke. At the point e., -Fig. 4 the new closesand the furtherinward motion of the f piston is accompanied by an increaseiof pressure'until the point b in Fig. \4 is reached. i a At this point] the pressure in the chamber A-is the same as the pressure behind the iston orces the airffrom the cylinder into t e air chamber. By the time the iston has 1 reached the end of its stroke an all the air except that in the clearances ace hasbeen forced into the air chamber, t e ressure in the chamber has been raised slightly. This rise in ,pressuredrives'u E the small piston of y e rod 6" sothat b can enga e the pin 5*. The'rod a is also enga I with the piny a and all the mechanism is new inyposition to begin the second cycle of operation:

v The amount of oil injected depends on the position ofthe governor and is independent of the action of b, 6 and their connections, but the length of time the valve 1) is open is indirectly dependent on the amount of oil injected. If much oil is injected the pressure in the air chamber will not fall so rapidly as when only a small amount is injected. The mechanism is so adjusted that the oil is injected at an accelerair receiver A; and the oil pumpa. is

controlled by the governor (not shown) through the we a and the striker a.

That the only timethe .valve b closes simultaneously with the shutting ofi of the oil is' when the engine is under maximum load, at'all the lighter loads the oil injection ceases, before the valve fb closes. The

,spark plug need only be in action in starting the engine, and gasolene is only used in starting. As soon as all parts have become.

. sufficiently heated the heat of compression for all compressions of over 150 pounds together with the heating action of the cylinder walls is all that is required to ignite the oil on entering thecylinder.

The size of the air chamber A bears the proper ratio tothe size of the cylinder so that the required change of pressure takes place in it for operating the unlocking mechanism of the valve 6. a V

The pressure employed in the chamber A and which constitutes the maximum pressure in the cylinder may be such as to best meet the mechanical requirements of, construction. Moderate pressures, between 200 and 300 pounds are contemplated but the ressure may be carried up to the limits set y mechanical construction.

The form of the air chamber should be such that the air which is forced into it from the cylinder will remain apart from the cooler air in the body of the chamber in as far as this is pos'ible.

To stop the engine draw back the starting lever s when the arm 0 is down which will cause it to catch the arm 0 and hold it and all parts connected with it from being returned by the spring a This prevents the pawl rods a and b from engaging the pins a and b and the engine now works as an air compressor, drawirig air in through the valve 6 and discharging it through the valve b which is controlled by the pressure in the now acts as a check valve. The valve in the pipe p is now opened and while the engine is losing its inertia, air is compressed and forced into a separate air tank to be used in starting.

A modification of the characteristics of this engine is shown diagrammatically in Fig. 5. Here the governor controls the time of closing of the air intake valve 6, regulating the amount of air retained in the cylinder. At heavy loads the amount of air retained is greater than at light loads. The air receiver valve closes simultaneously with the cessation of fuel injection, resulting in The solid lines in-Fig. 5 represent a.

hypothetical indicator diagram at a ve heavy load of the engine, while the dotted lines represent a very light load.

I am aware that internal combustion engines have been built on the constant pressure principle employing a separate compressor; or using one side of the piston for a compressor and the other side for the working side; also engines of the Diesel type compressing air in the working cylinder'and injecting the oil with an oil pump or by means of compressed air compressed by a separate air compressor. I, therefore, do not fclalm any of the methods used by these engines in operating upon a similar thermal cycle: but what I claim as new and desire to secure by Letters Patent, is:

v 1. In an internal combustion engine of the two or four cycle type, having essentially a. cylinder, a. crank shaft and a piston traveling close in to the cylinder head and compressing air on the inward stroke which was drawn in on the preceding outward stroke or delivered to it in two cycle operation; the combination therewith of an air chamber closed by a valve, said air chamber containing compressed air of a pressure but slightly less than the highest working pressure of the engine, and of such a size that the pressure is only slightly increased by receiving the entire charge of air compressed by the lnward motion of the piston, connected to the cylinder by a passage beyond the innermost travel of the piston, into which the fuel is injected on the following outward stroke.

2. In an internal combustion engine of the two or four cycle type, having essentially a cylinder, a crank shaft, a piston traveling comes higher than the pressure in the air chamber and closes when the pressure in the .air chamber drops a definite amount. a

. i P. A. LAWRENCE.

Witnesses:

H. H. Hnnnmeso1-r, F. Z. Tunas. 

